Clothes drier



April 24, 1951 w. L. KAuFFMAN. u 2,550'118 CLOTHES DRIER w .Filed July51, 1944 3 Sheets-Sheet 1 z INVENTOR.

April 24, 1951 w. L. KAUFFMAN, u

CLOTHES DRIER 5 Sheets-Sheet 2 Fiiled July 51, 1944 fi/J INVENTOR. want:w

ATTORNEY.

pr'l 24, 1951 w. L. KAUFFMAN,

CLOTHES DRIER 3 Sheets-Sheet 3 Filed July 31, 1944 INVENTOR.

ATTORNEY.

theV drum casing. z

Patented Apr. 24,v 1 951 CLOTHES DRIER Walter L. Kaufiman, II, Eric,Pa., assignor to Lovell Manufacturing Company, Eric, Pa., a corporationof Pennsylvania Application July 31, 1944, Serial No. 547,380

7 Claims. 1

The present invention relates to clothes driers of the type in which theclothes are tumbled in a rotatable drum and dried by heat and airsupplied to the drum.

The object of my invention is to provide an improved construction andarrangement in driers of this type having, among other advantages, animproved arrangement for handling lint and a simplified control. i

In the accompanying drawings, Fig. 1 is a front perspective of thedrier; Fig. 2 a rear view with the back panel of the cabinet removed;Fg. 3 is a, perspective of the cabinet base; Fig. 4 is a detail of thebelt tightener; Fig. 5 is a frag-V I mentary view of the lint filter;Fig. 6 is a control diagram; Fig. 6a is a perspective of the push buttonand temperature control; Fig. 7 is a section on line 'i-T Aof Fig. 2;Fig. 8 is a section on line 8-8 of Fig. '7; Fig. 9 is a top plan view ofthe cabinet base and exhaust duet; Fig. 10 is a section throughthetrough leading to the exhaust fan inlet; Fig; ll is a detail of theadjustment for `Referring to the drawings, there is shown a drier'havinga cabinet supportedA on abase 2. Tothe back section 3 of the 'base isfixed a box section column 4 carrying a bearing bracket 5 for a shaft 6fiXed to the back end 1 of a drum 8. The front end, 9 of the drum has acentral fianged opening IQ having a running clearance Withia circularflange ll on the front section of the cabinet. Except while clothes are`being loaded or unloaded, the opening defined by the fiange Il isnormally closed by a door 12 having a cylindrical projection [3extending into the drum. When the door is closed, the fiow of air f intoand out of the drum is confinedto the outer periphery Id which is ofperforated metal. On the inner periphery of the drum are axial ribs, |5lwhich provide a better grip for tumbling the clothes during rotation ofthedrum. v

`'The drum is enclosed by a closely fitting casing having front and backends |5, l'l respectively,

supported by stiffening members IB (Figs. 7, 8)

adjacent the front cabinet section and by the column 4. The ends |6, I'lare provided with inwardly extending peripheral flanges IQ around whichis wrapped a sheet 20 formingthe center section Vof the drum housing.The ends of the Sheet are secured to brackets 2! (Fig. 11) by bolts 22which permit a peripheral shifting of the sheet. As shown in Figs. 2 and11, the ends of the sheet 20 are spaced apart, part of the space beingfilled by a reflector 23 for a heating element 24. Along one edge of thereflector is a slot 25 through which air fiows to the drum. The airfiowing to the slot 25, as shown in Fig. ,7, is taken' increases fromthe front to the back of the w cabinet where it terminates in a circularflange 28 connected by a fiexible tube 29 to the intake 30 of acentrifugal fan 5| mounted on the rear section 3 of the base. The fandischarges parallel to the rear section of the base through an opening32 (Figs. 3, 9) into a duct 33 between a removable plate 34 and a sidesection of the base. At the front of the duet is a filter screen 35slidable to one side to permit access to the duet to remove lint and afixed filter screen 36 forming a common wall between the -duct 33 and aby-pass passage 31 having its inlet 38 between a defiector M and theinner end of the filter 35. The air discharged from the fan is guidedalong the duet by a deflector 39 on the rear corner of the duet andfiows past a thermostat bulb 40 supported by braekets 40a and past thedeflector 4! to the filters 35, 36 at the front corner of the duct. Thefilters are arranged to set up a swirling motion of the air at the frontcover tending to deposit lint along the inner surfaees of the filters.The defiector M extends into the duet beyond the by-pass inlet 38 in thedirection of air flow so that under normal operation any air fiowinginto the inlet 38 must turn a sharp corner which keeps lint out of theinlet until the'filter screens are filled to capacity. If the filterscreens are filled to capacity, theair, with any entrained lint, fiowsout through the by-pass inlet 38 which is of sufiicient area to providefor nearly normal air. fiow through the fan. The presence of lint at thefrontof the by-pass passage 3? indicates to the operator that the filterscreens need cleaning. Because the air flow is maintained, there is nofire hazard if the filter screens are not cleaned.

The action of the defiector 4| in keeping lint out of the by-passpassage during normal operation is partly due to inertiaseparationresulting from the fact that the air fiowing to the inlet 38 must turn asharp corner and partly to an injector action produced by the air streamfiowing past the defiector. So long Vas the filter screens are notelogged, these effects are sufficient to keep lint out of the by-passpassage.

The fan and drum are driven by a motor 132 mounted on the top of thedischarge duct 33 (the plate 3d being removed to permit access to themotor bolts) and having a double pulley 43, one part of which drives theblower through a belt M and the other part of which drives the drumthrough a double belt reduction consisting of a drum pulley 45 and anidler pull'ey Mi. The idler pulley is carried on a stub shaft projectingVfrom a bracket 41'! pivotally and slidably carried in an arm 48 fixedto the column 4. The belt tension is maintained by a spring 49.

The motor is Controlled by a push button switch D having contacts 5|connected in one side 51a of a 220 volt power line to which is connected(through conductors 5lb, 5Ic) the motor, a pilot light 52, (throughconductor Sid) and one side of a heating element Z (through conductor 5le). The switch also has contacts 53 connected in the other side 53a ofthe 220 volt power line and through a temperature limiting thermostat 54(and switch 58) to the other side of the heating element 24. Thetemperature limiting thermostat 54 is carried by the drum casingadjacent the heating element and prevents excessive temperatures in thedrum in case the normal air fiow through the drum is not maintained oris interrupted. Normal air fiow might be interrupted by clogging of thedischarge duct, by failure of the belt drive to the fan, or by openingthe door 42.

The most common cause of operation of the temperature limitingthermostat is the opening of the door, which permits the air to fiowdirectly to the drum and out through the trough 21, bypassing the normalcirculation of air and permitting heated air to accumulate adjacent theheating element. Under normal conditions with the door closed, the airenters the drum solely through the slot adjacent the heating element anddistributes the heat throughout the drum. The thermostat 54 is of theautomatic resetting type so the circuit to the heating element isre-established as soon as the temperature drops to a safe value.

At the start of the drier operation the push button switch is closed,establishing the circuits to the motor, pilot light, and heating elementand causing the r-otation of the drum to tumble the clothes and theoperation of the blower to crculate heated air through the drum.

During the initial part of the drying operation, the cabinet 'and theparts enclosed are heated and the temperature of the air exhaustedthrough the duct 33 rises at a rather rapid rate. After this initialrise, which, of course, would not be present if the drier were warm, thetemperature of the exhaust air is held down by the evaporation ofmoisture from the clothes. The evaporation of moisture proceeds at asubstantially constant rate until the clothes approach drynes's, whenthe rate of evaporation decreases and the temperature of the exhaust airgradually increases. Upon reaching' a temperature determined by anadjustment 55, a bellows 56 associated with the thermostat 40 expandsand moves the push button switch to the open position in which it isheld by an over-center spring 57. .By the adjustment which varies theposition of the actuator 50a of the push button switch relative to thebellows 55, the drier can be shut down when the exhaust temperaturecorresponds to the desired moisture content of the clothes. Theadjustment may be of common construction such as a screw thread actuatedby turning the push button. It is therefore possible to have the clothescompletely dried or dried to a degree suitable for ironing. Because thetemperature of the exhaust air is relied upon for controlling the drier,it is important that the air circulation through the drier be maintainedthroughout its operation. This is attained by the by-pass iduct 31 whichhas an unrestricted inlet .38 of sufficient sie to maintain thenecessary air flow even though the filter screens are clogged.

The efficiency and safety of the drier is increased by the drum casing|6, l'l, 20 which confines and directs the air fiow through the drum.Room temperature air drawn into the cabinet through openings 28 ispreheated by the drum `casing before reaching the intake slot 25. Theair fiowing through the intake slot fiows past the tumbling clothes andout through the trough 21. Because of the close fit of the drum withinthe casing, air currents are set up which sweep lint into the trough andkeep the inner surface of the drum casing clean. The thermostat bulb 40,be ing located between the fan exhaust 32 and the by-pass inlet 38, iskept clean by the rapidly moving air so lint does not accumulate on thebulb and insulate it so as to interfere with its operation. Even afterthe Velocity of the air is reduced by the clogging of the filter screensit is sufficient to keep the thermostat bulb clean. The thermostat shutsdown the drier before the temperature increases to a point at which theclothes might be iniured. Since the higher temperature prevails when theclothes are dry (or nearly dry) damage to the clothes is prevented.

While the fastest drying is obtained with the full heat, there are somefabrics, such as wool, which cannot stand the moderate temperatures(l35-145 F.) present with full heat. For these fabrics, part of theheating element is open circuited by a switch 53 normally closed by aspring 69 and openedV by an arm 6| on the push button shaft 62 when thepush button is turned to set the adjustment 55 to the low temperature(1l0-1l5 F.) suitable for Woolens and rayons.

. For all except the lowest temperature adjustment the switch 58 isclosed. The drier operates in the same manner as before, but with lowertemperature, the temperature gradually rising at the start, levellingoff due toevaporation, and rising at the end of d'rying to effectautomatic shut down.

In manufacture, the operative parts of the drier are, assembled on thebase, the drum 8 and drum casing 5-24 being mounted on the column z 4,the blower 3! being mounted on the rear section 3 of the base, and Vthedriving motor 42 being mounted on the top wall of the exhaust duct atone side of the base. The exhaust air thermostat M is connected to thecontrol wiring (by 10-- cating its bellows 56 with respect to the pushbutton switch) and mounted on the plate 34 which is positioned in theside of the exhaust duct. After assembling the rem'aining parts thefront section of the cabinet, the front, top, and side walls, is thenfastened to the base and the cabinet assembly completed by attaching theback wall of the cabinet.

The pilot light 52 and the push button switch 55 are mounted on platesin the upper front wall of the cabinet.

For service, the pilot light 52 and push button switch 50 aredisconn'ected and the back wall and then the front section of thecabinet is removed, exposing all of the operative parts of the drier forservice Operations.

What I claim as new is:

1. In a Clothes drier, a Casing, a Clothes receiving drum thereinrotatable to tumble the Clothes, a fan for exhausting air from thecasing, a discharge duct for the fan, a filter for the duct including apart extending back toward the fan -and along a Wall of the duct, and aby-pass passage having a common Wall with said part and p having aninlet on the fan side of said part.

2. In a Clothes drier, a Clothes receiving drum rotatable to tumble theClothes, a Casing surrounding the drum, a heater radiating heat throughan opening in the casing to the upper periphery of the drum, an airinlet to the casing adjacent the heater, an air outlet in the lower partof the casing, an opening'at one end of the drum and casing for loadingand unloading Clothes, a closu're' for said opening whereby the airlfiow through the drum is normally confined Vbetween said inlet andoutlet, a fan having its intake connected to said outlet for exhaustingassne cause fiow of air into said casing, and means forming an outletfor air from said casing in- Cluding a duct having a 'lint arrestingscreen, and another duct at an angle to said first named duct connectedto said first duct at a place reached by the air before it reaches saidscreen.

6. In a Clothes drier, a casing, a Clothes receiving drum thereinrotatable to tumble the Clothes, f fan means for discharging air fromthe casing,

a duct for the air stream discharged from the Casing by the fan means, afilter screen for the duct intercepting the' discharged air stream, a

' passage by-passing the filter having its inlet effecair at a ratesuchthat the Clothes* temperature 3. In a Clothes drier, a casing, a Clothesreceiving drum therein rotatable to tumble the Clothes, an air exhaustduct from the casing, a filter for the duct discharg'e'including a partextending back toward the intake end and along a Wall ofv the duct, andan effectively unobstructed bypass passage havingv a common wall withsaid part and having an inlet on the intake side ofV said part.

4. In a Clothes drier, a Casing, a Clothes receiving'drum thereinrotatable to tumble the Clothes,

a heater radiating to the drum, a discharge duct i for. air and lintfrom the casing, a filter for the duct, an eifectively unobstructedby-pass from the duct for air and lint in excess of the capacity of thefilter, and a thermostat in the duct in front of the by-pass passagevforCutting off the heater at a predetermined air temperature.

5. A Clothes drier comprising a stationary casing, a rotatable. Clothesdrying support in said casing,'heating means in said casing, means totively unobstructed and arranged 'with respect to the direction of airfiow so air entering the passage must turn a Corner'whereby lint is keptfrom the passage.

7 In a Clothes drier, a casing, a Clothes receiving drum thereinrotatable to tumble the Clothes, fan means for discharging air from thecasing, a duct for the air stream discharged by the fan means, a filterscreen intercepting the discharged air stream, a passage by-passing thefilter having an eif'ectively unobstructed inlet, and means defiectingthe discharged air stream beyond the inlet as regards the direction ofair fiow for keeping lint from the passage until the filter is clogged.

WALTER L. KAUFFMAN, II.

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